This invention relates to signal processing of acoustic signals in a body of water and particularly to a multiplexer system wherein the output of a plurality of spatially distributed acoustic and environmental sensors in an array is combined to form a single composite signal for transmitting and decomposing thereof at the receiving end.
Most of the methods presently in use for multiplexing signals from spatially distributed sensors in an array system are too large and too heavy to allow packaging of a large multi-element array and associated hardware in a sonobuoy package. Furthermore, such multiplexers consume too much power to allow continuous operation over extended periods of time within the capacity and limitations of the sonobuoy battery. Besides, none of these multiplexers is capable of theoretically bandwidth utilization efficiency over 50 percent. Since a sonobuoy radio channel is bandwidth limited, the acoustic performance that can be designed into the array is limited by the bandwidth utilization efficiency. Furthermore, the cost of present day multiplexers is too high for their use in a routinely expendable manner. It is thus desirable to have a multiplexer which is light, relatively inexpensive, and consumes very little power.